Changes

[[file:oiloil-and-oilsource-rock-correlations_fig8-8.png|thumb|{{figure number|4}}From Hatch et al.<ref name=ch08r18 />); reprinted with permission from AAPG.]]

[[file:oiloil-and-oilsource-rock-correlations_fig8-8.png|thumb|{{figure number|4}}From Hatch et al.<ref name=ch08r18 />); reprinted with permission from AAPG.]]

[[:file:oiloil-and-oilsource-rock-correlations_fig8-8.png|figure 4]] is a gas chromatogram of saturates from an Ordovician-sourced oil from the Illinois basin. It shows a low-wax oil derived primarily from the primitive organism ''Gloeocapsamorpha prisca''. Samples derived from ''G. prisca'' show strong odd-carbon preferences up to ''n''-C₁₉, and have very low concentrations of both pristane and phytane.<ref name=ch08r44>Reed, J., D., Illich, H., A., Horsfield, B., 1986, Biochemical evolutionary significance of Ordovician oils and their sources: Organic Geochemistry, vol. 10, p. 347–358., 10., 1016/0146-6380(86)90035-5</ref><ref name=ch08r28>Longman, M., W., Palmer, S., E., 1987, Organic geochemistry of mid-continent middle and late Ordovician oils: AAPG Bulletin, vol. 71, p. 938–950.</ref><ref name=ch08r18>Hatch, J., R., Risatti, J., B., King, J., D., 1990, Geochemistry of Illinois basin oils and hydrocarbon source rocks, in Leighton, M., W., Kolata, D., R., Oltz, D., F., Eidel, J., J., eds., Interior cratonic basins: AAPG Memoir 51, p. 403–423.</ref><ref name=ch08r17>Guthrie, J., M., Pratt, L., M., 1995, Geochemical character and origin of oils in Ordovician reservoir rock, Illinois and Indiana: AAPG Bulletin, vol. 79, p. 1631–1649.</ref>

[[:file:oiloil-and-oilsource-rock-correlations_fig8-8.png|figure 4]] is a gas chromatogram of saturates from an Ordovician-sourced oil from the Illinois basin. It shows a low-wax oil derived primarily from the primitive organism ''Gloeocapsamorpha prisca''. Samples derived from ''G. prisca'' show strong odd-carbon preferences up to ''n''-C₁₉, and have very low concentrations of both pristane and phytane.<ref name=ch08r44>Reed, J., D., Illich, H., A., Horsfield, B., 1986, Biochemical evolutionary significance of Ordovician oils and their sources: Organic Geochemistry, vol. 10, p. 347–358., 10., 1016/0146-6380(86)90035-5</ref><ref name=ch08r28>Longman, M., W., Palmer, S., E., 1987, Organic geochemistry of mid-continent middle and late Ordovician oils: AAPG Bulletin, vol. 71, p. 938–950.</ref><ref name=ch08r18>Hatch, J., R., Risatti, J., B., King, J., D., 1990, [http://archives.datapages.com/data/specpubs/basinar3/data/a134/a134/0001/0400/0403.htm Geochemistry of Illinois basin oils and hydrocarbon source rocks], in Leighton, M., W., Kolata, D., R., Oltz, D., F., Eidel, J., J., eds., Interior cratonic basins: [http://store.aapg.org/detail.aspx?id=1182 AAPG Memoir 51], p. 403–423.</ref><ref name=ch08r17>Guthrie, J., M., Pratt, L., M., 1995, Geochemical character and origin of oils in Ordovician reservoir rock, Illinois and Indiana: AAPG Bulletin, vol. 79, p. 1631–1649.</ref>

==G. prisca==

==G. prisca==